A cospojatioh



E. H. LICHTENBERG TRACTOR Original Fil-ed Feb. 26. 1919 2 Sheets-Sheet l 2 Sheets-Sheet 2 TRACTOR E. H. LICHTENBERG Original Filed Feb. 26, 1919 Dec. 18. 1923.

I [five/7101 idw.

patented 1%, .1923c OF VISCGNSIN.

TRACTOR.

Original application filed February 26, 1919, Serial Noe 2'?,53355.

January 28, 1920,

To all whom, et' may coi/cervi.'

Be it known that l, Enron' ll. lneY '71 at Milwaukee, in the county ot Milwa liee 5 and State ot fViscfmsin7 have invented certain nen7 and useful. improvements in Tractors, olf which the following is a specilicl s tion, the saine beingr a division o'l my copending application for patent tor traction 10 grading machine, Serial No. 279,235, tiled February 26, 1919.

The present invention relates to tractor devices, and has 'for its object to provide a device of this character which embodies novel features ot construction whereby it can be used 'for 'the support 'of a. heavy superpose/d load and Will not die in7 when encountering; soft places in the-,surface o" the ground over Which the tractor moving'.

The tractor has been more particularly designed for utilization in connection with traction grading machines Where any tendency of the tract r to dig in7 would be very objectionable, although it will be obvious that the usefulness of the tractor construction is not restricted to particular type of niachines or mechanism.

Further objects of the invention are to provide a traction device which has a strong; and durable construction, which will support a heavy superposed load, which is powerful in its action, and which has the necessary movement relative to the superposed load for adjusting itself to unevenness or inequalities in the surface of the ground over which the tractor is moving although the tractor is mounted and driven in such a manner that there is no tendency of the tread to dig in when a sott place is encountered in the surface of the ground.

For a l'ull understanding` of the invention reference is to be had to the following;` description and accompanying drawings which illustrate one oi many possible einbodiments of the idea involved, and in Which:

Figure l is a diagrammatic viciv and shows a traction device of the type embodying; the invention operatively mounted under a iframe upon which the load to be carried is superposed.

Figure 2 is an enlarged side elevation of Serial No. .Medie-6.

the ti ction deviea, showing more elearlf the construction and manner ot' imnintinltr thereoi.

Figure l a transverse sectional view on the line S-Lil of l `iggure 2.

Figure d is a similar view on line i-1l oit Figure 2.

'lorrespondinig and like parts are relier ou to in the following deso'iption and indica in all of the views' olf the drawings by the same reference characters.

Referringa to the drawings, which illustrate one pcssibe embodiment of' the inven- 65 tion., the numerals l` designate the sinn i side channels of the iframe, the opposite ends of the side channels boing; provided with the respective bearings 2 and El within w rich the transverse sl are jorui'ialed. 70 rFliese shafts carry the rollers or drums 5 around which the endless tread passes, said tread being` oi some suitable and known construction, and being shown as composed ot a series'orp tread sections which are 75 pivotally connected at 'i'. The bearings for the rear shaft are preln'ably adjustably nuiunted so that they can be moved to take up any looseness in the articulated tread. As illustrated the rear ends of the 8o side channels l are bii'urcated or slotted. at S to receive the bearings 3 said bearings being;` slidable within the bitu cations and l eing` operatively enga-ged by adjusting` bolts 9. Nuts 10 are applied to these adiustingi` 9,5 bolts 9 and provide a means for lowing;` the same in an adjusted position.

rlhe lower stretch ot the articulated tread is in direct engagement with the surface of the ground over which the traction device is oo traveling', and is sui'iported at the top there ont by a series of rollers ll.. These rollers 1l are arranged in pai f which connected by transverse shafts l2. rFliese shafts are journaled in bearings 13 proxued in a es hearing,` block l-t which is arranged under the side channels l and l carried thereby. yThe rollers ll engage edge portions oi. the tread section 6 and hold the saine in proper position.

The liorvvzwd sha'lt ft is provided with a rear wheel l5 which meshes iith a smaller rear .lo on a load supporting shalt l? which entends transversely across the caterpillar iframe at anintermediate point in the length thereof. This shaft 17 is shown as journaletl within a bearing block 18 fitted between the side channels 1, the ends of theshaft projecting laterally from opposite sides of the tractor and being received within bearings 19 at the lower ends of brackets or hangers 20 which are pendant from the superposed frame A upon which the load to be carried is placed. A sprocket wheel 21 is operatively connected with the gear wheel 16, being shown in the present instance as rigid therewith. This sprocket wheel receives power from seine suitable source for driving the tractor device and, for this purpose, a chain 22 is shown as connecting the said sprocket wheel to a sprocket 23 on a drive shaft 2/1 which is journaled on the main frame A and may receive power from any source. There will, of course, be a tendency for the entire tractor device to rotate bodily about the shaft 17 and, owing to the arrangement of the driving gear this will result in a tendency to lift or elevate the nose of the traction device and prevent it from digging in.

The rear end of thc frame is provided with a pair of plungers 25 which extend upwardly on opposite sides of the tractor and have a yieldingengagement with the main frame A. The lower ends of the plungers 25 pass loosely through openings in outstandingl flanges 26 projecting` from yokes 27 which span the bifurcations 8 of the side channels 1. The upper ends of the plungers 25 are each slidably received within a pair of guide collars 25% which have a coil spring 29 interposed between the same. These springs surround the respective plungers 25 and engage flanges 30 at the ends of the guide collars. The upper set of guide collars 28 are slidable within openings provided in a plate 31 on the main fran'ie A, the flanges 30 engaging the lower face of thc plate to prevent upward movement of the guide collars through the plate, although the collars can have a limited downward movement against the action of the springs 29. rThe lower set of guide collars 28 are slidably received within openings provided in brackets 32 which are arranged under the plate 31. The flanges 3() ofthe lower set of guide collars 2S engage the upper faces of the brackets 82 to prevent downward movement of the guide collars therethrough although the guide collars can move upwardly against the action of the springs 29. Sleeves 33 are fitted upon the lower ends of the plungers 25 and interposed between the lower set of guide collars 28 and the outstanding flanges 2G of the tractor frame, and the extremities of the plungers 25 are capped by the nuts 34. Writh the construction which has just been described it will be obvious that the rear end of the frame is normally held yieldingly in the correct position for movement over level or smooth road surfaces. However, the tractor frame has a limited rocking movement about the load supporting shaft 17 so that the tractor can adjust itself to inequalities in the surface of the ground @vor which it is traveling. In other words, the rear end portion of the frame is held yieldingly at its proper position for ordinary operation by means of the spring plungers which connect the frame to the main frame, although the caterpillar is adapted to rock bodily upon the shaft 17 as an axis for the purpose of accommodating itself to variations in the surface of the ground over which it travels. The manner of mounting and driving the tractor device is such that it will not have a tendency to dig in when a soft place is encountered in the surface of the ground, and heavy loads can be carried and properly supported without difficulty. This is due to the fact. that when the machine is moving forward the direction of rotation of the driving gear is such that thc tendency of the entire tractor to rotate therewith will tend to Swing' the forward end of the tractor upwardly and elevate the same. This feature of construction is especially advantageous in connection with traction grading machines of the general character described in my previously mentioned co-pending application, since any digging in of the supporting tractor would necessarily interfere with the proper grading action of the machine.

lVhile I have specifically described one particular embodiment of the caterpillar traction device.y it will be obvious that ,it is susceptible of many modifications and changes without departing from the spirit of the invention.

Having thus described my invention what I claim as new is:

1. A traction device, comprising a frame, an endless tread operating on said frame, a transversely disposed load supporting shaft engaging an intermediate portion of the frame and about the axis of which the frame is adapted to rock, a drive wheel loosely mounted on the said load supporting shaft, a drive connection between the drive wheel and the endless tread, and means for applying power to the drive wheel, said drive wheel rotating in such a direction as to tend to lift an end portion of the frame.

2. A traction device, comprising a frame, an endless tread on said frame, a trans versely disposed load supporting shaft engaging an intermediate portion of the frame and about the axis of which the frame is adapted to rock, a drive wheel loosely mounted on the said shaft, means for applying power to the drive wheel, a gear rigid with the drive wheel, and a drive connection between the gear and the endless tread, the drive wheel rotating in such a direetion as to tend to lift the forward end of the frame.

3. A device, comprising a frame, front and rear drums thereon, an endless tread extending around the said drums, a transversely disposed load supporting shaft engaging an intermediate portion of the frame and about the axis of which the frame is adapted to rook, a drive wheel loosely 10 mounted on the said shaft, a gear rigid with the drive wheel, and a gear rigid with the front drum and Ineshingwith the said gear 0f the drive wheel, the drive wheel rotating in such a. direction as to tend to 15 lift the forward end of the frame.

In testimony whereof I affix my signature.

ERICH H. LICHTENBERG. 

